Malting apparatus

ABSTRACT

A malting vessel has a vertical tube set within it, with its ends spaced from the top and bottom of the vessel, and there is a feed screw or a gas stream active in the tube so that a circulation of contents may be set up throughout the vessel, at will. Air or other gas at controlled temperature, humidity and pressure can be injected into the vessel at any time. When a feed screw is used it preferably has a special construction, with a conically flared lower end, the pitch of the screw in this region being progressively inversely proportional to its diameter. A novel method of malting involves the setting up of a circulation of grain in a vessel in such a way that part of the grain batch is rising while another part is falling, gas being optionally injected at least into the part of the circulation where grain is falling.

United States Patent Primary Examiner-Robert W. Jenkins A!r0rney Larson,Taylor and Hinds ABSTRACT: A malting vessel has a vertical tube setwithin it, with its ends spaced from the top and bottom of the vessel,and there is a feed screw or a gas stream active in the tube so that acirculation of contents may be set up throughout the vessel, at will.Air or other gas at controlled temperature, humidity and pressure can beinjected into, the vessel at any time. When a feed screw is used itpreferably has a special construction, with a conically flared lowerend, the pitch of the screw in this region being progressively inverselyproportional to its diameter.

A novel method of malting involves the setting up of a circulation ofgrain in a vessel in such a way that part of the grain batch is risingwhile another part is falling, gas being optionally injected at leastinto the part of the circulation where grain is falling.

T MOTOR CONTROL PATENTED JUH29 IQTI SHEET 1 BF 4 MOTOR CONTROL MALTINGAPPARATUS This invention relates to malting apparatus, and a method ofmalting,

Developments in malting in past years have led away from the floor typeof malting which involves large floorspace and high labor costs, towardsthe use of apparatus where grain can be malted in considerably greaterdepth. Problems have been encountered, in malting vessels which workwith grain in depth, in ensuring uniformity of temperature and otherconditions with consequent control of growth and modification over thewhole batch. Mechanical stirring as distinct from circulation requiresrelatively great power, only takes place in one part of the grain andsets up no general circulation throughout the vessel. Attempts to usepneumatic stirring (e.g. Popp U.S. Pat. No. 2,891,892, United KingdomPat. No. 1,044,029) have concentrated on sudden injections of gas tocause explosive upheavals in the grain bed.

The present invention on the other hand provides for a continuous orintermittent circulation throughout the batch in the vessel during timeswhen control is required, and for the injection of gas or gases ofdesired temperature and humidity into the grain either during itscirculation or when stationary so that all parts of the batch of grainare kept under the correct conditions during the process. Whencirculating, all parts of the batch get, over a period of time, anexposure to standardized and controlled malting conditions.

This invention has for an object the provision of apparatus and methodswhereby the malting of any grain, particularly barley, may be carriedout under controlled conditions with high efflciency, that is to saywith great evenness of temperature and other conditions in andsurrounding the grain being treated.

According to one aspect of the invention, apparatus for malting grainincludes a vessel containing an inner vertical tube having ends spacedfrom the top and bottom of the vessel, elevating means to move grain inopposite vertical directions inside and outside the inner tube and meansfor passing gas into the vessel.

The elevating means may be pneumatic, for example. a noz zle directed todischarge gas up the inner tube and served by a high-pressure gas inletor may be mechanical, for example, a feed screw located within andcoaxial with the inner tube, with control means for the temperature andhumidity of the gas used for the pneumatic lift, if provided, and forthe gait or gases passed into the vessel. In addition, a rotatableagitator may be provided at the bottom of the vessel, and there may befurther controllable inlets, erg. gas or additives. I

There may be provided in the outer part of the vessel aerating legsarranged to be served with gas at any desired temperature, humidity andpressure and to discharge it into the grain being treated. Convenientlythe legs may extend over at least the greater part of the length of theinner tube.

Near the lower end of the outer part of the vessel there may be inwardlydirected air nozzles arranged to discharge air into the grain to preventarching or bridging thereof.

A feed screw preferably is formed around a central shaft which has aconical skirt at its base portion, the base portion of the screw beingformed around the conical skirt and fitting within a correspondingconical flared portion of the inner tube. The base portion ofthis screwmay have a pitch which is progressively inversely proportional to thesquare of the diameter of the conical skirt.

According to another aspect of the invention I provide a method ofmalting grain which includes maintaining grain circulation in avessel bylifting part of the grain at one portion of the vessel and at messmetime allowing part of the grain to fall in another to formatcirculation. The method may include passing gas into the vessel duringthe circulation to enter at least that part of the grain which isfalling in the vessel.

The vessel and method may be used either solely for the aerobic stage ofmalting or for any or all stages of any method of malting known to me.For example in a method which includes an anaerobic phase a charge ofbarley may be placed in the vessel, may be steeped in the vessel andsubjected to aerobic and/or anaerobic phases in the vessel, thecirculation and aeration facilities of the vessel being used as requiredduring the aerobic modification phase or phases or during both aerobicand anaerobic phases. On the other hand, since the malting vessel is amore costly piece of capital equipment than'the simple containers andvessels which would be required for steeping and/or initiatinggermination, the grain may be held in other vessels of a simplerconstruction during those stages and transferred to the present maltingvessel only for certain other stages, e.g. its aerobic and/or anaerobicphases.

Particular embodiments of the invention and methods of carrying it outwill now be described with reference to the accompanying drawingswherein:

FIG. 1 is a diagrammatic side elevation of a first embodiment,

FIGS. 2 and 3 are detail sectional views of parts of that embodiment,and

FIG. 4 is a diagrammatic side elevation ofa second embodiment.

The first embodiment of the invention is shown in FIGS. 1, 2 and 3 ofthe drawings.

The vessel is a closed-ended cylindrical drum set with its main axisvertical. The vessel is made in three portions, the center portion 1being a hollow open-ended cylinder having end flanges 2, 3, a top'closure 4 of the vessel being attached to flange 2 by a like flange 5,and a bottom frustoconical portion 6 of the vessel being attached toflange 3 through a hollow ring portion 7 which will be more particularlydescribed later.

The bottom end of the frustoconical section 6 is closed by a closureplate 8.

The top closure 4 bears a mounting 9 for an electric motor 10 and alsoan inlet pipe 11 for grain and a narrower inlet pipe 12 for anyadditives that may be required to be used. There is also a wide gasoutlet 13 fitted with a closure and release valve (not shown).

In the cylindrical portion 1 there is provided a valved outlet pipe 14,leading to a floater box for receiving dust and other solid matter whichit may be desired to remove from the vessel, and a first gas gallery 15which has a gas inlet 16. There are three or more protruding feet 17 atthe lower part of this portion strengthened by trunnion plates l8 andhorizontal gussets 19 for those plates. The feet are for supporting thevessel, preferably through load cells for indicating the-total weight ofvessel and contents. The ring 7 forms a second gas gallery and has a gasinlet 20.

In the frustoconical portion 6 there is provided a sight glass 21equipped with an internal wiper (and other sight glasses may be providedat suitable points over the whole of the ves sel), an arch-breaking airjet 22 and a discharge port 23 equipped with a power-operated openableclosure door which is gastight when closed.

In the baseplate 8 there is provided a bearing boss 24 receiving thelower end of a shaft which extends coaxially with the motor 10, a drainoutlet 25 and a gas withdrawal outlet 26 which has a valved drain 27 ina branch.

A shaft 28 of the drive motor 10 is coupled through a flexible coupling29 to a hollow shaft 30 which extends as far as the bearing boss 24 inthe baseplate of the vessel. This bears a feed screw 31 which at thebottom flares outwardly around a conical skirt 32 on the shaft 30 andends in a shovel portion 33 traveling over the baseplate 8. Above wherethe screw 31 terminates four paddles 42 project mutually at right anglesto each other from the shaft and at the base a paddle 34 is provided.The paddle 34 is offset from the axis of rotation of the screw to sweepoutwardly any grain falling inside the conical skirt 32.

The conical skirt 32 terminates at the level of the lowermost revolutionof the screw and reinforces its radially inner edge. The paddle 34 joinsthe skirt 32 adjacent the shovel part 33 of the screw.

The screw 31, together with its portion which surrounds the conicalskirt 32 works inside a stationary inner tube 35 which is supportedwithin the vessel by stays and spacers such as 36, 37, and has at itsbottom end (FIG. 2) an outwardly flaring tube part 38 which has narrowelongate slots 39.

The portion of the screw 31 which surrounds the conical skirt 32 has aconformation such that the pitch of the screw is at any one timeinversely proportional to the square of the diameter of the skirt 32which forms its inner boundary. This is to ensure that material, as itis drawn up outside the skirt 32 and inside the flared tube part 38, isnot axially compressed as it progresses into regions of successivelylesser diameter. We call this part of the assembly, the scroll. Alongthe length of the cylindrical part of the tube 35 the screw pitch isconstant.

The shovel portion 33 of the screw 31 is reinforced on its radiallyinner side by the extreme bottom end part of the skirt 32 and on itsoutside it has an upstanding edge lip 40 so that it forms a shovel forscooping up grain lying on the bottom plate of the vessel.

This bottom plate has an upper perforated decking 41 which has narrowslits of a size to permit drainage of liquid downwardly withoutpermitting grain to pass. The perforations allow also for the passage ofgas through the base.

The bottom of the conical part 38 of the tube 35 is spaced above thedecking 41 of the baseplate 8, and the shovel 33 works within thatspacing. The paddle 34 displaces outwardly any grain which falls insidethe radius of the shovel, and gas jets 2 are positioned around theperimeter of the upper decking 41, but in the outside wall of theconical portion 6 of the vessel, ready to be used should any bridging orcavitation occur in the region of the gap between the decking 41 orportion 6 and the tube portion 38.

A small nozzle 45 can be fed with gas or liquid through an inlet 46 inthe bushing construction 24 so as to wash or blast off grain which mightbe in the area of the bottom portion of the shaft 30, and in thebaseplate 8 there is a drainage outlet to permit flow-away of any liquidpassing through the decking 41, and gas suction outlet 26 will be usedto assist in the rapid displacement of one type of atmosphere by anotherwhen need be.

The outlet door 23 has a guillotine slide plate 47 powered by, forexample, a hydraulic ram, which slide plate when closed forms a gastightseal with the bearings in which it runs.

Referring now to FIG. 3 there is shown the construction of the hollowring 7 which acts to secure together the part 1 and part 7 of the vesseland acts also as a gas gallery for the input of gas into the vessel. Thering is generally of channel construction, the base 50 of the channelbeing a cylinder and its sidewalls 51 and 52 being parallel,horizontally disposed and bolted to flange 3 of the vessel 1 and thecorresponding flange of the portion 6, respectively. The mouth of thechannel section which is thereby disposed inwardly of the vessel iscovered by some foraminate covering 53 for permitting gas to pass freelybut prevent grain from accumulating in the gallery.

The construction of air gallery 15 is similar insofar as a foraminatemember is provided and an annular gas channel around the circumferenceof the vessel 1.

The hollow shaft may have perforations in it so that aeration of thegrain may be continued even as it is being moved upwardly by the screwwithin the casing 35.

In use, barley or other grain, which may be as harvested or which may bein any suitable stage of the malting process is admitted through thecharging pipe 11. It falls into the gap between the inner tube and theouter wall of the vessel and charging is continued until a desiredamount of grain is in the vessel. The depth of grain in such a vessel isvery considerable. Experimentally, I have worked with grain depths of 7feet or more, and a charge of 2 tons weight (when containing its desired44-50 percent of moisture.)

If the grain was admitted in its harvested condition, it is steeped inthe vessel, water being added through inlet 12 at a controlledtemperature. Aeration during steeping may be carried out. A watercirculation may be set up by using the drain outlet 25 and inlet 12.After the steep, an aerobic germination period follows, and during thisphase the motor 10 drives the shaft 30 and hence the screw 31 inrotation in such a sense as to lift grain from the bottom of the vesselto the top. The motor 10 may be of variable speed, and be controlled inits operation through a conventional control 42 by temperature or othercondition sensing means 43 in the vessel. When the grain arrives at thetop of the screw it is evenly distributed outwardly with the aid of thepaddles 42 and there is thus set up a continuous and even circulation ofthe grain through the vessel, it being lifted by the screw 31 and thenallowed to fall, outside the inner tube 35. During this circulation gasis fed under controlled temperature and humidity conditions through oneor both gas galleries 7, 15, through their respective inlets 20 and 16,so that there is a gas flow upward through the grain which is fallingdownwards in the outer portion of the vessel. Gas having passed throughthe grain is exhausted through the pipe 13 and may be discharged to theair or may be recirculated after temperature, composition and humidityconditionmg.

A charge of 2 tons weight being circulated at a rate so that there isone complete changeover each 5 minutes will suitably be supplied withair at a rate of approximately 800- 1,000 cu. ft./min.

In the present embodiment there is a counterflow of grain and gas.During this phase the grain is chitting and rootlets are just emerging,and the continuous circulation and admixing ensures evenness of the rateof this development (as far as is at all possible) throughout the wholemass of the grain, and helps prevent matting of any rootlets which maybe developing.

The vessel may also be used during an anaerobic phase or a resteepingprocess in which the rootlets are killed-the grain may be left staticduring this phase, the atmosphere inside being changed either activelyor by virtue of respiration for one of CO or other nontoxicnonrespirable gas (or water in the case of resteeping), or thecirculation of grain may be continued. CO or other gas may be passedinto the vessel through gas galleries 7, 15.

The circulation facility may be used at any stage. When it is used, itassists a controlled and evenly dispersed supply of gas to the grain.

To unload the vessel, gas and other input is stopped, the door slideplate 47 is opened and the screw 31 driven in the opposite direction tothat which would cause lift so that the shovel part sweeps round thebaseplate and continuously disturbs the grain at the bottom of thevessel and pushes it out through the door 23.

During either the aerobic or the anaerobic stages conventional maltingadditives may be provided, and water may be added in liquid form as wellas by humidification of the gas. The gas used is dependent on the stagein the malting at which it is used, and may be air and/or carbondioxide, or may be a mixture of carbon dioxide and another nontoxicnonrespirable gas.

The second embodiment of the invention uses as elevating means, insteadof the screw 31, an air current. This embodiment is showndiagrammatically in FIG. 4. The chamber 60 is fabricated in stainlesssteel and has a column about 10 feet high and 4 feet 6 inches indiameter, of generally cylindrical form, the lower part 61 of thechamber tapering inwardly. Located vertically within the chamber andcoaxial therewith is an inner tube 62 corresponding to casing 35, thebottom end 63 of which is about 9 inches from the bottom of the chamberand about 12 inches in diameter, while the top end 64 is about 2 feetfrom the top of the chamber and about 9 inches in diameter. Convenientlythe inner tube is tapered in the bottom portion, the tapered part 65being about 2 feet 6 inches to 3 feet long. Just above the top end 64,but spaced therefrom by a few inches, is a deflector having upper 66 andlower 67 conical deflecting surfaces, and above this is an inlet 68 forthe grain. This is formed in the top wall of the chamber and is providedwith means for ensuring an airtight seal. Also in the top wall of thechamber are a water inlet 12 having valve means to control the flow ofwater and a gas outlet 70, fitted with a pressure release valve that maybe set to allow the escape of gas from the chamber at atmospheric orother predetermined pressure. Gas received by the outlet can berecirculated, as will be described. Thermometers, pressure gauges andglass inspection windows are provided in the wall of the chamber wherenecessary.

Level with the top of the inner tube there is an outlet pipe 71 havingvalve means and communicating with a floater box 72.

Gas galleries 7, 15, are provided as before, the wall of the chamberbeing provided with grilles which constitute the inner wall of thegalleries and permit gas to pass into the chamber.

The number and disposition of the galleries may be varied as required.Alternatively, or in addition, there may be gasifying legs consisting ofa number of vertical tubes 75, blind at their lower ends and aperturedalong their length (the apertures may be larger or more frequent towardsthe blind end), arranged vertically approximately midway between thewalls of the outer chamber 60 and inner tube 62. There may be anyrequired number of legs, say six or eight, extending as far as from thelevel of the top 64 of the inner tube to the level of its bottom 63. Attheir upper ends, the legs are connected via a gas-distributing ring 76to an exterior gas supply through gas inlet 77. I

Such gasifying legs may be provided in the first embodiment described.

A gas nozzle 78 is located in the middleof the bottom wall of thechamber and extends vertically up into and coaxial with the inner tube62, the nozzle projecting about 12 inches into the lower end ofthistube. The nozzle is served with high-pressure gas (e.g. air at apressure of the order of 3() psi.) from a suitable external s0urce'79 ata predetermined or controllable temperature. The bottom wall 80 of thechamber has an aperture communicating with a closable discharge outlet81, and above the bottom wall of the chamber there is a mechanicalagitator 82 consisting of radially extending arms arranged to berotatable by means 83 below the chamber and including a suitable sourceof power such as an electric motor, whereby the radial arms may becaused to rotate and sweep across the bottom of the chamber andfacilitate movement of the grain. The bottom wall of the chamber also isprovided with an outlet 84 for liquor with a suitable control valve.

The gas nozzle 78 may be so mounted as to be adjustable in heightrelative to the lower end of the inner tube.

In operation of this embodiment, barley or other grain which may alreadyhave been steeped is charged through the inlet 68 onto the upper surface66 of the deflector and is filled to the required extent. Water at adesired temperature may be introduced into the chamber in apredetermined quantity for adjustment of the moisture content. During anaerobic phase gas at the desired temperature and pressure and which maybe recycled from the outlet 70 is introduced through the ducting systemvia the upper and lower galleries 7, 15, to pass through the grillesinto the body of the grain and out through the gas outlet. The highpressure gas inlet to the nozzle 78 is opened and a current ofgas movingat the desired speed, pressure, and temperature passes up the inner tube62.

Grain at the bottom tapered part 61 of the chamber 60 is forced radiallyinwardly as it falls under gravity so that it comes underneath the lowerend 63 of the inner tube 62. where it is entrained by the gas streamfrom the nozzle and begins to be carried up the innertube, its placebeing taken by more grain passing in radially at the bottom, while theelevated grain is deflected by the lower surface 67 of the deflector atthe top 64 of the inner tube so as to pass radially outwardly and fallupon the grain at the top ofthe chamber. A circulation of the grain isthus built up and in a short time a steady rate of flow will have beenobtained so that the grain is moving up the interior of the inner tubecontinuously and is deflected outwardly so as to fall down into and fillthe space between the outside wall of the inner tube 62 and the wall ofl the chamber 60. This continues until the chamber has been thenrecirculating down round the outside of the inner tube and is eventuallyagain passed up the inner tube.

This recirculation may be continuous throughout a given phase oftreatment of the grain, or may be interrupted.

It may be necessary to alter the moisture content after steeping, andthis may be done by adding water or spraying from a suitably disposeddevice, or by controlling the humidity ofthe gas used.

In this embodiment the grain is thus subjected to various influenceswhich will dissipate local rises in temperature. First, the grain in theinner tube is being subjected to gas of a predetermined temperatureserved through the nozzle; secondly, the falling grain is subjected tothe passage of the gas from the grilles in the upper and lower gasgalleries, whereby gas is caused to pass constantly through the body ofthe grain; and thirdly, the constantly moving grains are continuouslymingled. In addition, the agitator 82 may be employed further to minglethe grains. The first-mentioned of these is a facility not afforded bythe first embodiment.

After the desired processing of the grain has been accomplished, theoutlet aperture in the bottom of the chamber is opened and if and whenrequired the agitator is employed to assist efficient emptying of thevessel through the outlet aperture.

The agitator 82 may be a rake with upstanding teeth, or it may be ofblade form.

The provision in these embodiments of the various facilities describedenables malting to be accomplished by any method known to me and with agreater degree of control than heretofore. The whole of the malting, oronly one or more parts of the whole process may be performed in thevessel. Owing to these being carried out in a closed chamber, anydesired microclimate may be established and maintained as regardstemperature, and humidity and environment of gas and air surrounding thegrain. The instrumentation may be elaborated by the provision of sensingmeans located in any desired places in the apparatus, wherebytemperature gradients may be sensed and corrected, e.g. by alteration ofthe air temperatures at the galleries, legs or in the nozzle, beforethey assume proportions of any magnitude.

The movement of the grain achieved by the lifting, effectively preventsmatting of any rootlets.

Apparatus embodying the invention can have a high-capacity size ratio incomparison with other malting apparatus, and is therefore susceptible toeconomic production of malt.

lclaim:

l. A malting apparatus which includes a vessel adapted to receive grainfor malting and containing an inner vertical tube having ends spacedfrom the top and bottom of the vessel, elevating means adapted toelevate grain inside the inner tube from the bottom of the vesseltowards the top, gas inlet means adapted to pass gas into the vessel atleast adjacent the bottom of the vessel, and gas outlet means adapted topass gas from the vessel at the top of the vessel, whereby acountercurrent of gas passing from gas inlet to gas outlet may be set upinside the vessel against grain elevated by the elevating means andfalling outside the tube from the top of the tube to adjacent the bottomof the vessel.

2. A malting apparatus according to claim 1 wherein the elevating meansis a nozzle directed to discharge gas up the inner tube and served by ahigh-pressure gas inlet.

3. A malting apparatus according to claim 2 wherein means are providedfor conditioning the gas discharged from the nozzle.

4. A malting apparatus according to claim 1 wherein the elevating meansis a feed screw, working in the inner tube and means are provided fordriving the screw in rotation.

5. A malting apparatus according to claim 4 wherein the bottom end ofthe screw sweeps a horizontal, planar baseplate of the vessel, anopenable outlet for grain is provided at the bottom of the vesselradially outside of the horizontal, planar baseplate, and the drivemeans for the screw are reversible whereby on reversal of the drivemeans and opening of the outlet, the bottom end of the screw aidsdischarge of grain from the outlet by pushing it from the baseplateradially towards and out of the outlet.

6. A malting apparatus according to claim wherein the said baseplate isperforated.

7. A malting apparatus according to claim 4 wherein, adjacent and abovethe top of the screw, there is provided a plurality of paddles rotatablewith the screw.

8. A malting apparatus according to claim 1 wherein said inner tube isstationary.

9. A malting apparatus according to claim 1 wherein the said gas inletmeans is a gallery peripherally around the vessel and having agas-passing surface flush with an inner peripheral wall of the vessel.

10. A malting apparatus according to claim 9 wherein the said wall has acylindrical portion and a frustoconical base portion and the saidgallery is provided in the said cylindrical portion, closely adjacentthe frustoconical base portion, and a second said gallery is provided,spaced from and above the first.

11. A malting vessel according to claim 1 wherein additional to the saidgas inlet means, at least one further gas inlet means is provided, at atleast one level between the first said inlet and the said gas outlet.

12. A malting apparatus which includes a vessel containing an innervertical tube having ends spaced from the top and bottom of the vessel,a feed screw acting to move grain upwardly inside the inner tube, meansfor driving the feed screw in rotation and means for passing gas intothe vessel at least outside the inner tube, the screw being formedaround a central shaft which has a conical skirt at its base portion,the base portion of the screw being formed around the conical skirt andfitting within a corresponding conical flared portion of the inner tube.

13. A malting apparatus according to claim 12 wherein the screwterminates at its base in a shovel part, protruding below the conicalflared portion of the tube and of a size to sweep, during onerevolution, the gap between the base of the flared portion of the tubeand the bottom of the vessel.

14. A malting apparatus according to claim 12 wherein the pitch of thebase portion of the screw is progressively inversely proportional to thesquare of the diameter of the conical skirt.

15. A malting apparatus according to claim 12 wherein the central shaftis hollow and has gas-passing apertures.

16. A malting apparatus which includes a vessel containing an innervertical tube having ends spaced from the top and bottom of the vessel,elevating means comprising a feed screw working in the inner tube tocause a lifting vertical movement of grain in the inner tube, the grainbeing free to fall outside the inner tube but inside the vessel,variable speed motor means to drive said screw means, and control meansto alter the speed of the motor in accordance with temperatureconditions sensed in the vessel.

1. A malting apparatus which includes a vessel adapted to receive grainfor malting and containing an inner vertical tube having ends spacedfrom the top and bottom of the vessel, elevating means adapted toelevate grain inside the inner tube from the bottom of the vesseltowards the top, gas inlet means adapted to pass gas into the vessel atleast adjacent the bottom of the vessel, and gas outlet means adapted topass gas from the vessel at the top of the vessel, whereby acountercurrent of gas passing from gas inlet to gas outlet may be set upinside the vessel against grain elevated by the elevating means andfalling outside the tube from the top of the tube to adjacent the bottomof the vessel.
 2. A malting apparatus according to claim 1 wherein theelevating means is a nozzle directed to discharge gas up the inner tubeand served by a high-pressure gas inlet.
 3. A malting apparatusaccording to claim 2 wherein means are provided for conditioning the gasdischarged from the nozzle.
 4. A malting apparatus according to claim 1wherein the elevating means is a feed screw, working in the inner tubeand means are provided for driving the screw in rotation.
 5. A maltingapparatus according to claim 4 wherein the bottom end of the screwsweeps a horizontal, planar baseplate of the vessel, an openable outletfor grain is provided at the bottom of the vessel radially outside ofthe horizontal, planar baseplate, and the drive means for the screw arereversible whereby on reversal of the drive means and opening of theoutlet, the bottom end of the screw aids discharge of grain from theoutlet by pushing it from the baseplate radially towards and out of theoutlet.
 6. A malting apparatus according to claim 5 wherein the saidbaseplate is perforated.
 7. A malting apparatus according to claim 4wherein, adjacent and above the top of the screw, there is provided aplurality of paddles rotatable with the screw.
 8. A malting apparatusaccording to claim 1 wherein said inner tube is stationary.
 9. A maltingapparatus according to claim 1 wherein the said gas inlet means is agallery peripherally around the vessel and having a gas-passing surfaceflush with an inner peripheral wall of the vessel.
 10. A maltingapparatus according to claim 9 wherein the said wall has a cylindricalportion and a frustoconical base portion and the said gallery isprovided in the said cylindrical portion, closely adjacent thefrustoconical base portion, and a second said gallery is provided,spaced from and above the first.
 11. A malting vessel according to claim1 wherein additional to the said gas inlet means, at least one furthergas inlet means is provided, at at least one level between the firstsaid inlet and the said gas outlet.
 12. A malting apparatus whichincludes a vessel containing an inner vertical tube having ends spacedfrom the top and bottom of the vessel, a feed screw acting to move grainupwardly inside the inner tube, means for driving the feed screw inrotation aNd means for passing gas into the vessel at least outside theinner tube, the screw being formed around a central shaft which has aconical skirt at its base portion, the base portion of the screw beingformed around the conical skirt and fitting within a correspondingconical flared portion of the inner tube.
 13. A malting apparatusaccording to claim 12 wherein the screw terminates at its base in ashovel part, protruding below the conical flared portion of the tube andof a size to sweep, during one revolution, the gap between the base ofthe flared portion of the tube and the bottom of the vessel.
 14. Amalting apparatus according to claim 12 wherein the pitch of the baseportion of the screw is progressively inversely proportional to thesquare of the diameter of the conical skirt.
 15. A malting apparatusaccording to claim 12 wherein the central shaft is hollow and hasgas-passing apertures.
 16. A malting apparatus which includes a vesselcontaining an inner vertical tube having ends spaced from the top andbottom of the vessel, elevating means comprising a feed screw working inthe inner tube to cause a lifting vertical movement of grain in theinner tube, the grain being free to fall outside the inner tube butinside the vessel, variable speed motor means to drive said screw means,and control means to alter the speed of the motor in accordance withtemperature conditions sensed in the vessel.